There's quite a few culprit in VBExpress, that would be really nice if you could post your VB and the whole PIC code here.

As you're using PORTA... make sure you have disabled the ADCs

PortA Doesn't Work & Common 8-Bit PIC® Microcontroller I/O Pin Issues (TB3009)
http://www.picbasic.co.uk/forum/showthread.php?t=561

Any specific reason why you don't use the built-in PIC USART?